TMS320C31, TMS320LC31

DIGITAL SIGNAL PROCESSORS

SPRS035B – MARCH 1996 – REVISED JANUARY 1999

26

POST OFFICE BOX 1443

changing XFx from an input to an output

The following table defines the timing parameter for changing the XFx pin from an input pin to an output pin.

The number shown in Figure 20 corresponds with the number in the NO. column of the table below.

timing parameters of XFx changing from input to output mode (see Figure 20)

NO.

’LC31-33

’C31-40

’LC31-40

’C31-50

’C31-60

’C31-80

UNIT

MIN

MAX

MIN

MAX

MIN

MAX

MIN

MAX

MIN

MAX

37

td(H3H-XFIO)

Delay time, H3 high to XFx

switching from input to output

20

17

17

16

9

ns

Execution of

Load of IOF

37

H3

H1

I / OxFx

Bit

(see Note A)

XFx Pin

NOTE A: I / OxFx represents either bit 1 or bit 5 of the IOF register.

Figure 20. Timing for Change of XFx From Input to Output Mode

reset timing

RESET is an asynchronous input that can be asserted at any time during a clock cycle. If the specified timings

are met, the exact sequence shown in Figure 21 occurs; otherwise, an additional delay of one clock cycle is

possible.

The asynchronous reset signals include XF0/1, CLKX0, DX0, FSX0, CLKR0, DR0, FSR0, and TCLK0/1.

The following table defines the timing parameters for the RESET signal. The numbers shown in Figure 21

correspond with those in the NO. column of the following table.

Resetting the device initializes the bus control register to seven software wait states and therefore results in slow

external accesses until these registers are initialized.

HOLD is an asynchronous input and can be asserted during reset.